As a heat exchanging apparatus enabling improvement in heat exchange efficiency by making a flow of a heat transfer fluid collide with another flow of a heat transfer fluid in a heat exchange flow passage, there has been known the heat exchanging apparatus as shown in FIG. 10 (Refer to Japanese Patent laid-open Publication No. HEI 7-294162).
In a heat exchanging apparatus 100 as shown in FIG. 10, however, since annular flow passages 118 are fabricated with pipes, it is difficult to fabricate flow passages with uniform dimensions, which makes it difficult to mass-produce the heat exchanging apparatus, and the cost is inevitably high. Furthermore, because of restrictions over the tube dimensions, sometimes it is impossible to fabricate a flow passage with optical design dimensions, and size reduction of the heat exchanging apparatus 100 is not easy.
When a heat transfer fluid flows from a communication pipe 119 into the annular pipe 118, the heat transfer fluid collides with a turbulent flow of the heat transfer fluid flowing in the annular pipe 118, and a velocity at which the heat transfer fluid collides with an inner wall surface of the annular pipe 118 substantially drops, which makes the heat exchange efficiency disadvantageously lower.
Collision of the heat transfer fluid with the inner wall surface of the annular pipe 118 occurs only when the heat transfer fluid flows into the annular pipe 118, and the collision does not occur when the heat transfer fluid flows out, and thus the heat exchange effect caused by collision of the heat transfer fluid with the inner wall surface of the annular pipe 118 occurs only once in one annular pipe 118. Therefore, for improving the heat exchange efficiency, it is necessary to increase a cross section of the annular pipe 118, or to increase the number of annular pipes 118.
Furthermore, in the heat exchanging apparatus based on the conventional exchanging apparatus, there is no specific design for a mounting angle of the communication pipe 119 to an internal surface of the annular pipe 118, nor for a form of the internal surface of the annular pipe 118 for maximizing the heat exchange efficiency during the collision.
In an application of the heat exchanging apparatus 100 in which a heat transfer fluid is flown into a heat exchange flow passage 110 by sucking air therein with a blower or the like, the heat transfer fluid flows without colliding with the internal surface of the annular pipe 118, so that the heat exchange efficiency in the heat exchanging apparatus 100 substantially drops. Because of the structure, the blower is required to be installed in front of the heat exchange flow passage 110.
On the other hand, there has been known the method for generating superheated steam as disclosed in Japanese Patent Laid-Open Publication No. HEI 10-337491, and in the method, an increase in temperature of steam is produced by sucking heated gas from an inflow port with an ejector blowing out steam at an ultrahigh speed from a nozzle thereof.
With the method for generating superheated steam, however, it is possible to obtain superheated steam flowing at a high speed, but sometimes clean superheated steam can not be obtained because of characteristics of the heated gas, and furthermore the gas is mixed with steam to form a mixture, and also in this case, highly pure superheated steam can not be obtained.
Especially, when a flame or a heated discharge gas is used, it is impossible to obtain superheated steam having ultrahigh purity required for cleaning, for instance, semiconductor wafers, and therefore the method can not be employed for cleaning. Furthermore, the method can not be employed in a clean room where use of a flame is inhibited.